Prebreeding research of near-isogenic lines of spring bread wheat with a combination of translocations from Agropyron elongatum (Host.) Р.В. and Aegilops ventricosa Tausch.

To protect bread wheat from pathogens and, in particular, rust diseases, introgressive resistance genes located in alien translocations are commonly used. However, their application in practical breeding demands prebreeding studies. They reveal effects of translocations on the adaptive properties of plants, performance indices, yield, and the quality of the final product. For this purpose, we studied the L653 and L654 near-isogenic lines of spring bread wheat cultivar Dobrynya, resistant to leaf rust and carrying the combination of translocations 7DS • 7 DL-7Ae#1L + 2AL • 2AS-2MV#1, which host genes Lr19/Sr25 from Agropyron elongatum (Host.) P. B. and Lr37/Sr38/ Yr17 from Aegilops ventricosa Tausch. The recipient cv. Dobrynya and standard cv. Favorite were used as references. Phytopathological tests showed that L653 and L654 were highly resistant to Puccinia triticina at all stages of plant development and to Puccinia graminis race Ug99 + Lr24 (TTKST), but they were moderately susceptible to the Saratov population of this pathogen. The prebreeding research of lines L653 and L654 showed that the combination of 7 DS • 7 DL-7Ae#1L + 2AL • 2AS-2MV#1 translocations: (1) prolonged the seedling emergence –heading time by 7 days and increased the mean plant height by 10 cm; (2) did not affect lodging resistance or 1000 kernel weight; (3) affected grain yield in neither drought years nor years of leaf rust outbreaks; (4) reduced plant adaptation to abrupt vegetation condition changes; (5) reduced gluten amount without affecting its strength, dough tenacity, tenacity : extensibility ratio, flour strength, bread volume, or bread porosity. Thus, the combination of 7DS • 7 DL-7Ae#1L + 2AL • 2AS-2MV#1 translocations in the genotype of spring bread wheat cv. Dobrynya determines high resistance to leaf rust and stem rust race Ug99 + Lr24 (TTKST), being neutral with regard to agronomic performance indices

Molecular identification of the stem rust resistance genes in the introgression lines of spring bread wheat

A total of 57 introgression lines and 11 cultivars of spring bread wheat developed by All-Russian Institute of Plant Protection and cultivated in the Volga Region were analyzed. The lines were obtained with the participation of CIMMYT synthetics, durum wheat cultivars, direct crossing with Agropyron elongatum (CI-7-57) and have introgressions from related species of bread wheat, namely translocations from Ag. elongatum (7DS-7DL-7Ae#1L), Aegilops speltoides (2D-2S), Ae. ventricosum (2AL-2AS-2MV#1), Secale cereale (1BL-1R#1S), 6Agi (6D) substitution from Ag. intermedium and triticale Satu. Cultivars and lines were assessed for resistance to Saratov, Lysogorsk, Derbent and Omsk stem rust pathogen populations (Puccinia graminis f. sp. tritici), and analyzed for the presence of the known Sr resistance genes using molecular markers. The analysis of the cultivars’ and lines’ resistance to the Saratov pathogen population in the field, as well as to Omsk, Derbent and Lysogorsk populations at the seedling stage, showed the loss of efficiency of the Sr25 and Sr6Agi genes. The Sr31 gene remained effective. Thirty one wheat lines out of 57 (54.4 % of samples) were resistant to all pathogen populations taken into analysis. The Sr31/Lr26, Sr25/Lr19, Sr28, Sr57/Lr34 and Sr38/Lr37 genes were identified in the introgression lines. The Sr31/Lr26 gene was identified in 19 lines (33.3 % of samples). All lines carrying the 1RS.1BL translocation (Sr31/Lr26) were resistant to all pathogen populations taken into analysis. The Sr25/Lr19 gene was identified in 49 lines (86 %). The gene combination Sr31/Lr26+ Sr25/Lr19 was identified in 15 lines (26.3 %). The gene combinations Sr38/Lr37+Sr25/Lr19, Sr57/Lr34+Sr25/Lr19 and Sr31/Lr26+Sr25/Lr19+Sr28 were identified in 3 introgression lines. These three lines were characterized by resistance to the pathogen populations studied in this work. The Sr2, Sr24, Sr26, Sr32, Sr36 and Sr39 genes were not detected in the analyzed wheat lines

A prebreeding study of introgression spring bread wheat lines carrying combinations of stem rust resistance genes, Sr22+Sr25 and Sr35+Sr25

The Sr22, Sr35, and Sr25 genes attract the attention of bread wheat breeders with their effectiveness against Puccinia graminis f. sp. tritici race Ug99 and its biotypes. The effectiveness and impact of Sr22+Sr25 and Sr35+Sr25 gene combinations on agronomic traits have not yet been studied. In the present article, these traits were studied using the spring bread wheat lines L503/W3534//L503, L503/Sr35//L503/3/L503 carrying the Sr22+Sr25 and Sr35+Sr25 genes during 2016–2020. These lines were assessed for resistance to P. graminis f. sp. tritici under natural epiphytotics and to the Saratov, Lysogorsk and Omsk populations of the pathogen and to the PgtZ1 (TKSTF) and PgtF18.6 fungus isolates in laboratory conditions (TKSTF + Sr33). The presence of the studied Sr-genes was confirmed by using molecular markers. Prebreeding studies were conducted during 2018–2020 vegetation periods. Under the natural epiphytotics of the pathogen and in the laboratory conditions, the Sr22+Sr25 combination was highly effective, while Sr35+Sr25 was ineffective. For grain yield, the lines with the Sr22+Sr25 and Sr35+Sr25 genes were superior to the recipient cultivar L503 in one year (Sr22+Sr25 in 2019; Sr35+Sr25 in 2018), with a decrease in 2020, but in general there were no differences. For the period 2018–2020, both combinations showed a decrease in 1000 grains weight and an increase in the germination-earing period. The line with Sr22+Sr25 genes showed insignificant effects on gluten and dough tenacity, but the ratio of dough tenacity to extensibility was higher, and flour strength, porosity and bread volume were lower; in the line with Sr35+Sr25 genes, the gluten content was lower, but the strength, tenacity of the dough and the ratio of dough tenacity to extensibility were higher, flour strength and the porosity of the bread were at the recipient level, but the volume of bread was lower

Study of resistance to leaf and stem rusts in Triticum aestivum–Aegilops speltoides lines

Presently, the use of bread wheat introgression lines resistant to pathogens in practical breeding is hampered by the lack of their cytogenetic characteristics, data on the genetic control of disease resistance, and influence of alien genetic material on grain productivity and quality. For the solution of these problems, two wheat–Aegilops speltoides lines, L195 and L200, developed at ARISER and resistant to leaf and stem rusts were studied. These lines were produced by crossing of spring bread wheat cultivars to line L26b-4. Cytogenetic analysis of the lines involved C-banding, meiotic analyses, and FISH with pAs1 and Fat. It allowed the rust resistance genes, efficient against both rust types, to be mapped to a 2D-2S translocation in both lines. Genetic analysis revealed tight linkage of leaf rust resistance genes from Ae. speltoides to gametocidal genes and absence of susceptible plants from the F2 hybrids and subsequent generations. Exceptions were found only in hybrid combinations with lines L2032 and L583: occasional susceptible plants were noted  in the F2 and subsequent generations. Evaluation of lines L195 and L200 revealed high resistance to Ug99 + Lr24 (TTKST) and a local Saratov population of stem rust. The prebreeding studies of lines L195 and L200 showed their benefits in breeding for grain productivity in comparison with the recipient cultivar L503 and good bread-making quality. Due to the complex of agronomical traits and high resistance to leaf and stem rusts, lines L195 and L200 can be considered promising donors for commercial bread wheat breeding

The effect of the 7DL-7Ae#1L·7Ae#1S translocation on the productivity and quality of spring bread wheat grain

The 7DL-7Ae#1L·7Ae#1S translocation with the Lr29 gene attracts the attention of bread wheat breeders by its effectiveness against Puccinia triticina. However, its impact on useful agronomic traits has been little studied. In this report, the prebreeding value of 7DL-7Ae#1L·7Ae#1S was studied in analogue lines (ALs) of spring bread wheat cultivars Saratovskaya 68 and Saratovskaya 70 during 2019–2021. The presence of the Lr29 gene was conf irmed by using molecular marker Lr29F24. The ALs with the Lr29 gene were highly resistant to P. triticina against a natural epiphytotics background and in laboratory conditions. 7DL-7Ae#1L·7Ae#1S in Saratovskaya 68 ALs reduced grain productivity in all years of research. On average, the decrease was 35 and 42 %, or in absolute f igures 1163 and 1039 against 1802 kg/ha in the cultivar-recipient. In Saratovskaya 70 ALs, there was a decrease in grain yield in 2019 and 2020, and there were no differences in 2021. On average, the decrease was 18 and 32 %, or in absolute f igures 1101 and 912 against 1342 kg/ha in the cultivar-recipient. The analogues of both cultivars showed a signif icant decrease in the weight of 1000 grains, which ranged from 14 to 20 % for Saratovskaya 68 and 17–18 % for Saratovskaya 70. An increase in the period of germination-earing was noted only in Saratovskaya 68 lines, which averaged 1.3 days. ALs of Saratovskaya 70 had no differences in this trait. 7DL-7Ae#1L·7Ae#1S did not affect plant height and lodging resistance in all ALs. Studies of the bread-making quality in lines with 7DL-7Ae#1L·7Ae#1S revealed a signif icant increase in grain protein and gluten content. As for the effect on the alveograph indicators, there were differences between ALs of both cultivars. While Saratovskaya 68 ALs had a decrease in elasticity and in the ratio of dough tenacity to the extensibility, Saratovskaya 70 lines had an increase in these indicators. All lines increased the f lour strength and the loaves volume, but while Saratovskaya 68 ALs had an increased porosity rating, Saratovskaya 70 ALs had the same rating as the recipient

Development of the genetic classification of Aegilops columnaris Zhuk. chromosomes based on the analysis of introgression lines Triticum aestivum×Ae. columnaris

Aegilops columnaris Zhuk. is a potential source of new genes for wheat improvement. However, this species has not yet been used in practical breeding. In the present work we have for the first time reported the development and molecular-cytogenetic characterization of T. aestivum×Ae. columnaris introgression lines. Analysis has not revealed alien genetic material in five of the 20 lines we have studied, while the remaining lines carried from 1 to 3 pairs of Aegilops chromosomes as addition(s) or substitution(s) to wheat chromosomes. Altogether, five different chromosomes of Aegilops columnaris have been detected in the karyotypes of 15 lines by C-banding and fluorescent in-situ hybridization (FISH). Based on substitution spectra, these chromosomes were identified as 3Ае1, 3Ае2, 5Ае2, 6Ае1 and 6Ае2. In addition, another Aegilops chromosome has been found in the line 2305/1 as a monosomic addition; due to the lack of group-specific markers we were unable to assign this chromosome to a particular genome or a genetic group and therefore it was designated Ае-а. In several lines acrocentric and telocentric chromosomes have been revealed (Ae-b and Ae-c). It is most likely that these chromosomes were derived from unknown Aegilops chromosomes due to a large deletion. A comparison of electrophoretic spectra of gliadins in introgression lines L-2310/1 and L-2304/1 with substitutions of chromosome 6D with two different chromosomes of Ae. columnaris (these lines were assigned to the 6th homoeologous group based on C-banding data) has shown that they carry different alleles of the gliadin loci. This observation confirmed that lines L-2310/1 and L-2304/1 contained non-identical 6Ae chromosomes. Taking into consideration our previous results of FISH analyses, three other Ae. columnaris chromosomes can be assigned to homoeologous groups 1, 5 and 7 of the U-genome based on the location of 5S and 45S rDNA loci (1U and 5U) or pSc119.2 probe distribution (7U). Thus, based on our current data as well as on the results of earlier work, we can identify eight out of the 14 chromosomes of Aegilops columnaris

PREHARVEST SPROUTING RESISTANCE IN SPRING BREAD WHEAT CARRYING CHROMOSOME 6Agi(6D) FROM Agropyron intermedium

A significant adverse effect of chromosome 6Agi(6D)-from Agropyron intermedium on preharvest sprouting resistance was foundin inbredlines (F7–F10 or senior) andnear-isogeniclines of red-grain andwhite-grain common spring wheat. The red-grain recombinant inbredlines, carrying this substitution chromosome, varied significantly in this trait, probably, owing to the genetic background effect. The causes of the adverse effect of chromosome 6Agi(6D) from Agropyron intermedium on preharvest sprouting resistance are unknown

<i>Triticum durum</i> Desf. is a valuable source for spring bread wheat genetic diversity enhancement

Background. Enhancement of the Triticum aestivum L. genetic diversity by means of alien chromatin, including that from Triticum durum Desf., is an important element in the breeding of bread wheat cultivars that meet modern requirements.Materials and methods. The study included the L153, L154 and L155 introgressive spring bread wheat lines produced from crosses between the spring bread wheat cultivars ‘L503’ and ‘L505’ and spring durum wheat cultivars ‘Yazi10’ and ‘Tarro’ developed in Mexico. Evaluation of these introgressive lines included phytopathological, phenological, genetic, and breadmaking analyses carried out with conventional methods both under open-air and laboratory conditions. Seventeen DNA markers were used to identify genes for resistance to Puccinia triticina Erikss. f. sp. tritici in the lines. The obtained data were statistically analyzed using the Agros-2.10 package of breeding and genetic programs.Results. Studying introgressive spring bread wheat lines L153, L154 and L155, developed with the participation of durum wheat cvs. ‘Yazi10’ and ‘Tarro’, showed that leaf rust resistance of these lines was induced by the Lr genes from durum wheat cultivars. The effect of the gene donor and the recipient cultivars on a number of useful agronomic traits was identified. The recipient cv. ‘L505’ was noted for its good combining abilities.Conclusion. Introgression of chromatin from durum wheat cultivars into the spring bread wheat gene pool made it possible to produce lines resistant to the local P. triticina population, as well as to some test clones of this pathogen. Such lines can be used as donors of the Lr genes. In addition, the L154 introgressive line combined good grain productivity and baking quality